The effect of cholesterol on vesicle size during freezing and thawing process of extruded egg phosphatidylcholine liposomes were studied by varying the length and number of freeze-thaw cycles. Laser diffraction particle size analysis showed that the volume median diameter of freeze-thawed egg phosphatidylcholine multilamellar vesicles was increased when cholesterol was included in the bilayers. Using a freeze-thaw cycle of 3 min freezing in liquid nitrogen at -196° followed by 3 min thawing at 50° resulted in an anomalously large particle size for egg phosphatidylcholine/cholesterol formulations. When egg phosphatidylcholine/cholesterol multilamellar vesicles were repeatedly freeze-thawed, the maximum size was achieved after five freeze-thaw cycles.
|Number of pages
|Indian Journal of Pharmaceutical Sciences
|Published - 2004
All Science Journal Classification (ASJC) codes
- Pharmaceutical Science